Processing apparatus for radiation detection devices



Jan. 6, 1953 M. N. FAIRBANK 2,624,253

PROCESSING APPARATUS FOR RADIATION DETECTION DEVICES Filed Nov. 14, 1951 I I I u u n FIG. 2

FIG.

lNVENTOR FIG. gs

Patented Jan. 6, 1953 P-RO' ICESSIN'G: APPARATUS FOR' RADIATION DETECTION DEVICES Murry N. Fairbank, Belmont, Mass., assignorto PolaroidTC'orporation, Cambridge, Mass, a-corporatio'n ofDelaware Application November 14, 1951, SerialNo.-'256,263

9 Claims.

1 Thisdnvention .relates to apparatus for process.- ing radiation-sensitive products ginthe nature of dosimeters of the character whichrutilize photosensitivematerial for. detecting, indicating, re-

between; the free ends .of .the arms ofxsaidsclip; and in the provision *of dosimeter processing apparatus of the character described making-,uuse of a box having a dooror a removable portion cording and measuring such radiation. 5 to permit the mounting within the box of said One embodiment of dosimeter which 'is "parspring-loaded, pressure-applying means-havingg a ticularly a'dapted' for processing by the. devices set pair of dosimeters engaged therebetween. forth hereinmahesuse of a releasably sealedzen- Other object of the invention willin partybe vel'opewhich :carries within it interior :photoobvious and will in partrappear'hereinafter. graphic materials, including a photosensitiveele- The invention accordingly comprises theapment-anda-rupturable container holding a-=photop tus possessing the construction, combination graphic-processing composition. Thewalllmemof elementsand arrangem'entoi' parts which are bers'of theenvelopeare substantial-1y impervious exemplified in the followingdetailed disclosure, to-actinic light, liquid and vapor-lbut. are formed and the s p of the application of which willzbe of materials which will transmit the nuclear indicated in the claims. radiation tobe detected. Process-ingota dosim- For a fuller understanding of t ature and eter of thischaracter is efiected by the 'applicaobjects of the invention, reference should he had tion-of pressure to opposite-sides of the envelope to the following detailed ption takenin in-amanner-toeffect the rupture of-the conconnefltion With the ccompanying drawings tainer therein and the appropriate spreading of Whereln! its dischargedliquidwithin'theenvelope. Figure 1 is a pe p Vi w f ne bodi- Objects-of 'the invention,whichpas noted, is merit of dosimeter p s ing. apparatus making concerned with me'ans for processingsphotosensiuse Of a box-type s r c ure..-and shows theaptive dosimeters ofthe character described'asin- Paratus with parts t r of r m v d and p r s comprisin a envelope en. 2'3 bIOkBIl away to detail the Interior of the closingat least-a photosensitiveelement-anda e nieans therein for applying pressure t th rupturable container holding a liquid composi- PPP S f apalr of dosimeters; tion,1'eside: in the provisionpf a simple, inex- 2 1S atransverse sectwnalview taken cenpensive=-and lightweightprocessing apparatus or trauy P the 0f h 1 1n assembled condition devicemmakmg f 1 box type container i and with the processing means removed fromth structure having-an opening through one 'end Q thereof-and employing spring-loaded, pressure- 3 a r lveview of a-retamer mema'pplying means inserta ble-within said box and 9: holdlng the box of 1 sc osedlconsimultaneously engage'ablein pressure contact 9 with the opposite sides of two "dosimeters and 4 15 a pelfspectlve w. ftheSI ring-IOadedL betweenwhich the-envelope of each dosimeter Pressure-applying fi usable with all embodiis individually movable upon pulling each enments of t invention f p lyi g ressure to velope-therebetweenwhereby'toefiect the-rupture the oplposlte sldes f each of a pairi f osimeters of thecontainer within the dosimeter envelope and i hy ses a pair of dosimand-the spreading of its liquid content, and 3 mounted Wlthln n ngaged between the wherein means are associated with thebox for spnPg'lQadedl pressure-applying means; removably mounting t I pring-loaded -means E1g. 5,-1sia perspective view oranother embodithe'rein inlop'erativealignment-with the opening h 0f p eter processing apparatus t mine."bDXLSOaSqwpermitipeach dosimeter be WhlCh thisv invention is concernedand illustrates manually engaged and pulled betweensaid 'presthevputslde of the apparatus; sure-applying meansand' to be=withdrawnfrom ig. 6 is a perspective view, with parts re said ho'xyin theprovision of dosimeter processing moved from the processing box of Ffig. 5., a d apparatus employing pressure-applying means shows the box In p n C i in the form of a pair of overlying and springig. '7 is. a plan view of ansenvelopeflosimeter loaded arms which are' removably mounted within of h type t W ich the processing apparatus a processing box ior applying pressure to the of i land 5 are usable;,and opposite sides of a dosimeter envelope, particu- Fig. 8 1s asectional elevatiorrrtakennalong the larly spring-loaded means in the form ofa- U- e 8 8 of Fig. 7. shapedjsp ging, clip t whicn rounded s. or Wh1le the present \invention is .lunconcerned cylindrical member is associatedfor -mountings With-radiations;detection;,devices per cse, .1t..:is'

3 nevertheless believed that a description of the construction of a dosimeter will assist in understanding the nature, operation and utility of the processing devices disclosed in Figs. 1 through 6 of the drawings. One embodiment of dosimeter which is particularly adapted for processing by the apparatus set forth herein is indicated by the general reference numeral in Figs. 7 and 8 and comprises an envelope formed of outer wall members H and 12 which are releasably secured together by means of a strippable adhesive bond along the longitudinal edges thereof and also transversely of the wall members at one end thereof, as well as at a position preferably, although not necessarily, somewhat from the other end. This bond is adapted to provide a seal between the layers which is impervious to liquid and to light of a wavelength actinic to photosensitive materials within the envelope 7%) and is shown in Fig. 7 at 73 as extending over an area lying between the rectangular marginal outline of the envelope as therein illustrated and the dotted line parallel to said outline. By this arrangement it will be apparent that each layer 'H and 72 providing a wall member will have a portion at one end which is unconnected to the other wall member. These portions 18 and 19, in the form of extensions, are in fact leaders which provide means to facilitate handling of the photosensitive unit, as Well as means to assist in stripping the layers so that they may be placed in spread-apart condition after processing.

The envelope wall members H and 72 are each formed of a sheet material which is substantially impervious to actinic light, liquids and vapor, while being capable of transmitting nuclear radiation to be detected, i. e., shorter wavelength radiation including X-rays and gamma rays. A print-carrying or print-receiving element (5, a rupturable container 11 for a liquid processing composition and a photosensitive element 14 are located within the interior of the envelope and are suitably secured to the inner surfaces of the wall members I! and 72, as shown in Fig. 8. Photosensitive element 14 comprises one or more strips of a photosensitive material, such as silver halide, while the print-carrying element 15 may comprise a suitable sheet material, such as baryta paper. In the arrangement shown, the print-carrying element 75 is in superposed relation with the portion of the photosensitive element M, while container 71 is located adjacent the end of the print-carrying element liwhich is positioned the nearest to the leader means of the dosimeter envelope. 1

A substantially liquid-impervious sheet material, similar to that used for forming the envelope wall members H and i2, is employed for container 77 whereby the container is adapted to hold a processing liquid. One example of a processing liquid usable for carrying out a silver halide transfer process comprises a silver halide developer and a silver halide fixer, both in solution in the liquid. The container Ti is positioned to extend transversely of the printcarrying element 15 and is provided with a rupturable seal adjacent the print-carrying element whereby pressure applied to opposite sides of the dosimeter envelope will effect the rupture of this seal and the discharge of the liquid content of the container for spreading between and in contact with the superposed print-carrying element 15 and the photosensitive element M.

For processing purposes, the dosimeter, as

noted, may be drawn between pressure-applying 4 means by pulling on the leader means 18 and E9 of the dosimeter whereby the container end of the dosimeter may conveniently be termed the leading end thereof and the opposite end of the dosimeter may be termed the trailing end.

Dosimeters of the character illustrated in Figs. 7 and 8 are intended to utilize a photographic transfer process in determining the extent to which the dosimeter has been acted upon by nuclear radiation of the type to be detected. As previously pointed out, the nuclear radiation to be detected will penetrate through the envelope. Radiation of this character will form latent image in the photosensitive materials of the photosensitive element 1 3. The processing liquid, when spread between and in contact with the printcarrying element and the photosensitive element, is adapted to develop latent image in the photosensitive element to silver and to form, by transfer, a reverse print thereof on the print-carrying element. Following formation of the reverse image, the envelope layers are peeled or stripped apart. The density of the transfer image is utilized to determine the extent of radiation dosage received by the dosimeter by comparing this density with a standard which is representative of print densities obtained by exposing photosensitive materials similar to those employed in the dosimeter to predetermined dosages of nuclear radiation.

The principles of a transfer process, as well as film structures and dosimeters suitable for use in the invention, are set forth in United States Patent No. 2,543,181, issued February 2'7, 1951, to Edwin H. Land for Photographic Product Comprising a Rupturable Container Carrying a Photographic Processing Liquid, application Serial No. 652,612, filed March '7, 1946, by Edwin H. Land for Liquid-Carrying Container and application Serial No. 218,042, filed March 28, 1951, by Murry N. Fairbank and William A. Shurcliif for Radiation Detection Devices. The last-noted application is specific to dosimeter constructions of the general nature of the dosimeter illustrated in Figs. 7 and 8 herein. Patent No. 2,543,181 and said copending applications include detailed descriptions of film units comprising a photosensitive element and a print-carrying element which are adapted to contain all of the photographic materials needed to process the unit. Also, the. just-mentioned patent and copending applica-. tions are detailed as to containers for holding.

processing materials and further include descriptions of liquid processing compositions usable With such units. The practices, photographic materials and compositions described in said Patent No. 2,543,181 and said copencung applicationsare generally suitable for carrying out the present invention and special reference to the details thereof are made in said patent and copending= Under the just-noted circumstances whereinthe dosimeter is literally intended to be processed at an mstants notice, it is desirable to provide processing means of simple and light-weight con-,.

.struction for association with the dosimeter,

Consequently, thebe carried on the-person, as by attachment to an article-of clothingor' by suspension? around the-neck from a ribbonor cord as in the. case: of the so-ca-ll'ed military dog tag; or: even: car.- ried in. a pocket. It is desirable that such an: apparatus, in addition to. providing processing means, should also serve several other. functions.

For example, th'e processing apparatus should: be in the nature of a-holderor carrier for storing or holding one. or more dosimeters. Like wise, the processing holder: should be able to. protect the:-stored. dosimeters:v from dirt, moisture; such: as perspiration, and. the like; while guarding. each dosimeter carried therein against the applicationof forces which: would rupture! the; liquid containeriof said dosimeter and while maintaining thedosimeter in1a=generally flat condition ready for: use. In addition, the: holdershould pro-e videmeans for. shielding. the, dosimeter: from soft rays which. might prematurely expose photosensitive materials within the dosimeter: envelope;.

One: embodiment of apparatus: for processing a dosimeter: of the character with which this. inventionisconcerned is'v generally indicated in Figs. 1 .and.2 by the reference numeral. l and comprises arectangular. box type of housing or structure which is closed at one end and open at the'other and which is adapted to have springloaded pressure-applying means 30,.such as thosedetailed in Fig. 4, removably; mountedor housed therein.

The housing of the apparatus. It comprises a top portion H and a bottom portion 12 having, side and end flanges whereby the portions I I and 12 maybe seated on each other to provide the boxtype of structure; As shown in Figs. 1 and 2, oneend of thebox is closed when-the top and bottom portions are inseated relation while the. other. end is provided with an opening 15. The. closed end: of the boxmay betermed the trailing end thereof and the end with the opening. I5 may. betermed the-leading; end. Top and bottom portions II and I2 maybe provided with suitable indexing pins and recesses (not shown) in thefiangesathereof whereby to facilitateregistration. of the box portions.

Means for securing the top and bottompon tions l l.- and: I2 in:superposedboxeforming relationship makes-guse. of a pair of. channels. or grooves I6 which are formedin theouter sur face of the body. of. the top and bottom box portions H and. [-2 to extend longitudinally thereof. adjacent each. long sidev of. the box... These channels l6 are adapted to receive the flanges l8 provided onspaced-apart, substantial.- ly Darallelarms of aU-shapedzretainer or keeper member I! (Fig. 3) which isslidably engageable with the sides and trailing end of. the box' formed by seating the top and bottom. box. portions. llv and 12 on each other. Fig. 2 shows the; top and. bottomv portions II and I2. assembled to. form the box-.type of structure and secured together.

by the retainer member [1- which is adapted to snugly-engagesaidtop and bottom portions: II and i2".

Additionally, the top portion of th'ebox [I may be provided with an. extension l4 having an opening therein for: receiving acord or ribbon. adapted to allow the apparatus In to be suspended from the person.

The. housing. for the apparatus It! may have the box-forming portions II. and I2 thereof con- Structect. from. any suitable material. preferably an: organic plasticimaterial, or they-maybe constructed of wood or suitable composite material or'even. light-weight metal, such as aluminum.

The retainer or keeper I'I' may be: formed from: similar materials.

In Fig. 4, there is disclosed spring-loaded means which are. used in applying pressure. to the opposite sides of a dosimeter envelope to effect theprocessing of the. dosimeter upon pu lling the envelope. between the. pressure-applying These spring-loaded means. 30 are means. shown in the'form of an elongated U-shaped spring. clip' havingoverlying arm portions3 l. and 32 which have alength fromtheir free ends. to the curved. portion. forming the base of. the U.-

shap'edclip somewhatless'. than the length of a.. dosimeterv to be processed. In. width, .each arm.

3! andl32 is approximately equal to'and' preferably slightly greater than the; width of. the dosimeter. Arms 3| and 32 areconstantly urged;

toward. each other by the nature of the construction of the spring clip. The clip may be made of any suitable spring metal.

Additionally, arms 3| and 32. at their respec-- tive free ends. are each formed with a. similarly rounded or generally curved portion indicated by reference numerals. 33 and .34, respectively;

When. viewed from. the outer surface. of eacharm 3| and 32, each curved portion is of concave shape, while the inner. surfaces of the curved portions are convex: whereby the arms 3|. and 32. protrude. toward each other at their free ends and in effect provide rounded jaws. These curved. portions 33 and 34 extend fully across each arm and are located transversely of the arms. The curved portions 33 and 34 each provide one spreading or pressure-applying surface of two pairs of. spreading surfaces utilized for processing apair of dosimeters adapted to be mounted between the arms 3| and 32 of the or cylindrical member. 35 is positioned between the convex surfaces of the curved portions 33 and 34 of the arms of the clip. Inasmuch asthe pressure needed for processing a dosimeter will be of the order of from two to five pounds, it will also be appreciated that the spring clip may be manually separated for insertion of the rod or cylinder 35 between the jaws thereof.

The spring clip of the pressure-applying means 30 is intentionally given a length dimension which is generally equal to thelength of a do simeter from the trailing end thereof to a loca tion which lies intermediately between the ends of the leader means '18 and 19, i. e.,.a position in advance of the container 11. This permits a pair of dosimeters to be inserted within or between the overlying arms 3| and 32 of the spring clip so that the trailing end of each dosimeter is located adjacent the curved base of the U-shaped' clip and so that a portion of the leader means. 18 and 19' is engaged between the spring-loaded pressure-applying. surfaces 33 and 34 and op-- It will be apparent that I the clip will befully spring-loaded when the rodv 7 posed surface portions of the rod or cylindrical member 35 with a portion of the leader means extending beyond the free ends of the arms 3| and 32 of the spring clip. This positioning of a pair of dosimeters within the spring-loaded pressure-applying means 30' is particularly well shown in Fig. 4, where, as illustrated, the dosimeters are located in overlying relation to each other and have their longitudinal axes generally parallel to the longitudinal axes of the arms 3| and 32 of the spring clip.

Operation of the processing device ID will now become apparent. In explaining this operation, it is assumed that the device is in unassembled condition and that all parts are completely separated from each other. A pair of dosimeters 10 are readily positioned within the pressureapplying means 30 by manually forcing apart the free ends of the spring clip and inserting the dosimeters between the overlying arms 3| and 32 thereof so that the envelope of each dosimeter has its trailing end adjacent the curved base of the U-shaped clip. The rod or cylindrical member 35 is then placed between the two dosimeters and will be held in position by the loading of the spring arms 3! and 32 of the clip, the surface of the dosimeter envelopes developing sufficient friction with the cylindrical member to allow it to be held in engagement by the curved portions 33 and 34 of the clip ends. Each dosimeter mounted within the clip will have a surface located adjacent one of the arms of the clip and will be engaged-between a curved portion 32 or 33 and a portion of the rounded surface of the cylindrical member 35. In mounting the cylindrical member 35, care should be exercised to position it so that it extends beyond each side of the U-shaped clip by substantially the same amount and so that the longitudinal axis of the cylindrical member extends generally transversely of the clip arms 3! and 32.

With a pair of dosimeters mounted within the pressure-applying means as just described, these means 30 may be seated within the bottom portion' |2 of the boxlike housing structure. It may be observed that each side wall of the bottom portion l2 of the box structure is provided with recesses 20 whereby to receive the ends of the cylindrical member 35 for the purpose of retaining it in operating relation to the pressure-applying means 30. Similar recesses are formed in the top portion ll of the boxlike structure. necessary to so support the rod or cylindrical member 35 in the recesses 25 that it is rotatable, although such practice falls within the scope of the invention.

The boxlike structure provided by the top and bottom portions H and I2 is, like the pressureapplying means 30, somewhat shorter than the dosimeters to be processed. As a result, when the pressure-applying means 35, with dosimeters inserted therein, are positioned within the bottom portion [2 of the box, the leader means of each dosimeter will extend through the end opening in the processing box.

With the pressure-applying means 30 mounted in the bottom portion of the box in the manner described, the top portion H of the box is seated upon the bottom portion and the retainer or keeper member I! is engaged, in the manner described, with the top and bottom portions I l and I2 of the box whereby to retain these portions together.

Processing of a dosimeter proceeds by grasping the processing device It in one hand and by then It is uni leader portion of one of the dosimeters 10 which extends through the end opening l5 of the box type of structure. Holding the processing apparatus Ill in this manner, a strong steady pull is exerted on the leader portion whereby to pull the dosimeter entirely between the spreading surface of a clip arm and of the cylindrical member 35. These spreading means exert a sufiicient pressure to rupture the container 1'! as the dosimeter is drawn therebetween and to cause the discharge of the liquid content of the container and the spreading thereof between the print receiving element 15 and the photosensitive element 14 whereby to initiate processing of the dos simeter.

After about a minute, the image-forming re? actions carried on within the envelope resulting from the rupture of the container and the spreading of its contents are completed. Following this, the dosimeter is peeled apart by grasping the unattached leader portions, one in each hand, and.

After the removal from the apparatus 10 of one of the dosimeters in carrying out the processing thereof, the second dosimeter may be allowed to remain in the apparatus until a time when it is desired to determine if the apparatus has been subjected to nuclear radiation. The remaining dosimeter may then be processed in' a manner similar to that already described. For re-use,

the apparatus is easily taken apart by sliding the keeper ll oil the box structure and separating the bottom and top portions thereof. This permits the pressure-applying means 30 to be removed and unprocessed dosimeters inserted therein.

It is desirable to provide the processing device with shield means to counteract the excessive efiect on the photosensitive portions of a dosimeter stored within the holder of soft rays such, for example, as X-rays of long wavelength which have low penetrating power. These shield means comprise a liner of a material tending to attenuate such radiation by an appropriate factor and may comprise lead or cadmium or other heavy metal or alloy. In Fig. l, shield members is are shown as individually carried by the innersurfaces of the arms 3| and 32. They may be fixed to the arms of the U-shaped clipby suitable means, asby screws or other fastenings or by the use of suitable cements and/or adhesives. It is also possible to mount either or both of the shields sides of the top and bottom portions of the box structure.

. Another embodiment of apparatus for processmg dosimeters of the character described is generally indicated in Figs. 5 and 6 by the reference numeral 50 .and comprises a rectangular box type of structure which is closed at one end and open at 'the other'and which is adapted to have "removably mounted therein the spring-loaded pressure-applying means 30 disclosed in Fig. 4. Box-5| may be constructed of any suitable mate- 'rial such as sheet metal, organic plastics, wood or composite material and maybe formed in one piece by molding or casting or may be formed by bending a suitably shaped blank or may be fabricated by securing individual structural members together.

'In the embodiment disclosed in Fig. 5. the box 5| is provided at the o en end thereof with a closure member'52 whi h is hin ed at one side of the box bv conventional hin e means 54 and is adapted to be secured in closedposition by a pin 55 enga eable with cooperatin tubular members or barrels 5S fixed to a side of the box 5| and to a side of the closure member 52. Indexing pins and recesses are il ustrated as provided at the open end of box 5| and the inner end of the closure member 52 for registering the latter with the box in closed position.

As ma be noted in Figs. 5 and 6. the closure member 52 is hollow and is provided with an opening 51 therethrough whereby to permit the free end of the leader means of one or more dosimeters mounted within the box 5| to extend through said opening and exteriorlv of the box and closure member. The interior of box 5!, at its o en end, is provided with a pair of recesses 58 located along the opposite long si es of the box. These recesses 58 extend inwardly from the o en end of the box for a distance at lea t suificient to receive the ends of the round rod or cylindrical member 35 of the spring-loaded pressure-applying means 30. Box 5! is shown as provided with an extension 53 hav ng an open ng therein for a suspension cord, ribbon or the like.

Operation of the a paratus 5|) is similar to that of the apparatus It). In the case o the apparatus 50. the closure member 52 is unfastened by withdrawing the pin 55 and the closure memher is then swung to the open position sho n in Fig. 6. The spring clip of the pressure-a plying means, with a pair of dosimeters inserted between the arms of the clip and the cylindrical member 35 in mounted position, is then inserted within the box 5|, with the curved base of the U-shaped clip positioned for location at the closed end of the box. Following this, the closure member 52 is swung to its closed position, with the leader means of each dosimeter extending through the opening 51, and the closure member 52 is fastened, after which each of the dosimeters may be processed by manually withdrawing them from the apparatus.

From the foregoing it will be appreciated that the apparatus forming the subiect of this invention accomplishes the aims and objects of the inventive concept. Each apparatus disclosed herein is of lightwei ht construction and is relatively small whereby it may be carried on the person. In addition, it is of a simple character that permits several dosimeters to be simultaneously stored and individually processed at an instants notice. Furthermore, dosimeters stored in the apparatus are adapted to be protected from dirt and moisture, as well as from forces which would tend to rupture the container within the dosimeter envelope due to the fact that, with the exception of a small portion of the leader means, each dosimeter is enclosed in the apparatus. Since these leader means are flexible, the portion thereof which extends from the apparatus dur- 10 ing storage of a dosimeter may be subjected-to considerable bending before a dosimeter mounted within theapparatus'becomes seriously damaged. Additionally, the apparatus of the invention permits means for shielding dosimeters storedtherein from soft rays which might prematurely expose the photosensitive materials within the dosimeter envelope. v

Since certain changes may be made in the above apparatus without departing from the scope of the invention herein involved, it is intended that all matter contained in the above description or shown inthe accompanying drawings shall be interpreted as illustrative and not in a limting sense.

What'is claimedisr 1. In apparatus for at least processing photosensitive dosimeters, each of the type having at least a photosensitive element and a rupturable container holding a liquid processing composition located relative to each other so that liquid discharged from said container may be spread over said photosensitive element, and wherein said photosensitive element and said container are carried in an elongated envelope provided with leader means at one end ther of to assist in handling and processing said dosimeter, in combination, a box type of structure having an opening through one end thereof, spring-loaded pressureapplying means, insertable in said box and adapted to have the leader means of a pair of dosimeters simultaneously engaged therebetween and extending therefrom and between which each dosimeter is individually movable upon pulling on the leader means thereof, for applying sufficient pressure to the opposite sides of each dosimeter to effect the rupture of the container and the spreading of its liquid content within said envelope as said dosimeter is pulled through said spring-loaded pressure-applying means, and means removably mounting said spring-loaded pressure-appl ing means in said box in operative alignment with said opening in the end of said box, whereby the leader means of each dosimeter envelope which is engaged by said spring-loaded pressure-applying means extends within said opening in said box for individual manual engagement.

2. Apparatus as defined in claim 1 wherein the spring-loaded means for applying pressure to the opposite sides of the dosimeter includes an elongated spring clip having two relatively wide overlying arms.

3. Apparatus as defined in claim 1 wherein said spring-loaded pressure-applying means comprises an elongated U-shaped spring clip and a rounded rod member removably engaged between the free ends of the arms of said U-shaped clip and in pressure bearing with said arms, whereby one dosimeter is positionable between the overlying arms of said clip for engagement between one arm and said rod member and a second dosimeter is engageable between the other arm and said rod member.

4. In apparatus as defined in claim 1, springloaded means comprising an elongated U-shaped spring clip having arm portions which are constantly urged toward each other, a rounded rod member removably engageable between the free ends of said arms and held therein by pressure contact of said arms, said rod member being located transversely of said arms and extending beyond opposite edges of each said arm.

5. Apparatus as defined in claim 4 wherein said box is provided with a recessed portion in opposite sides thereof adapted to removably receive the ends of said rod member.

6. Apparatus as defined in claim 1. wherein said spring-loaded pressure-applying means comprises an elongated U-shaped spring clip, each arm of said U-shaped clip at the free end thereof having a rounded portion which extends transversely of said arm and toward the other arm of said clip whereby to provide rounded surfaces for applying pressure to each dosimeter engaged by said spring-loaded pressure-applying means.

7. Apparatus as defined in claim 6, including a rounded rod member removably engageable between the free ends of the arms of said U-shaped clip.

8. Apparatus as defined in claim 1 wherein said 12 box comprises a top portion and a bottom portion superposable upon each other and means for securing said top and bottom box portions in superposed relation.

9. Apparatus as defined in claim 1 wherein said box is provided with a closure member at the open end thereof, said closure member being hollow and having an opening at one end thereof for alignment with the open end of the box, and means for securing said closure member to the end of said box with said opening in the closure member aligned with the open end of said box.

MURRY N. FAIRBANK.

No references cited. 

